There is, entirely understandably, a lot of bitterness about Maciel.
The problem is not in understanding a scoundrel (history is full of them) but in understanding his enablers.
The Vatican and John Paul II are among the most culpable, in approving constitutions that focus far too much on the personality of the founder, and then in refusing to investigate the serious complaints about Maciel.
Pius XII had removed Maciel from his order, investigated, and was apparently going to permanently remove Maciel when Pius died. The vicar of Rome covered up for Maciel, who then was in good graces when John XXIII appeared on the scene. The allegations about Maciel surfaced again under John Paul II, but no one took them seriously.
One issue is the difference between control and discipline. These are often confused both in theory and in practice, but the purpose and results are different.
Anyone who has been responsible for discipline in a family, a scout troop, or a middle school class, knows how difficult and thankless and necessary a task it is. Any organization needs discipline to achieve its purpose, and often to protect the weak. Discipline should also help those being disciplined to be disciples, to learn, to mature, to internalize rules, and eventually to be independent of outward disciple: the Law is a tutor.
But control, although it can look like discipline, is the tool of the narcissist or psychopath who wants to be the puppetmaster in his little (or big) universe. He wants to control even the minutest actions of those around him, and he keeps those around him infantilized and dependent.
In any organization, including the Church, narcissists tend to climb to the top, because they enjoy attention and controlling other people. I suspect that the Vatican has its share of narcissists, who saw nothing wrong with Maciel.
And Pope John Paul… No one knows why he failed. He was not authoritarian, despite that accusation against him. I suspect he was guilty of wishful thinking: The Legion looked so good, the accusations against Maciel couldn’t be true. A common human failing, but it can be disastrous when the self-deluder is in authority and is responsible for the discipline that protects the vulnerable.